How to distinguish the ranks of terracotta army

Usually , the way we know the ranks of army man is from their uniform and sign on it .it works for the terracotta warriors in Qin dynasty . the decotators on their uniform is the sign of rank .Another way , we know easier is from their hairstyles .fro example ,

The General had two knots on his hair piece , we call that butterfly hairstyle .but the soldier had only one .the difference is sommon soldier had one knot on the right side but the kneeling archer had on the left . Can you guess why was that ?